Greenhouse gas turns to stone in Iceland

The biggest surprise from the NORDICCS project came from Iceland, where researchers have developed a “quick fix” that converts CO2 into rock.

Edda Sif Pind Aradóttir of Reykjavik Energy with the result of CO2 injected into porous lava: A stable mineral that does not release the gas. (Photo: Terje Heiestad)

In the North Sea, CO2 can be stored in layers of water-bearing permeable rock or in depleted petroleum reservoirs beneath impenetrable cap rocks, but these formations do not exist around Iceland. Instead, the island’s volcanic geology is characterised by large expanses of porous basaltic lava, providing an opportunity for researchers to develop a completely new technology for CO2 storage.

“The Hellisheidi geothermal power plant outside Reykjavik emits roughly 40 000 tonnes of CO2 annually and 12 000 tonnes of H2S (hydrogen sulfide),” says Sandra Ó. Snæbjörnsdottir, a geologist at the University of Iceland. “We have experimented with dissolving greenhouse gases in water and pumping them underground. Our results indicate that over 95 per cent of injected CO2 converts to minerals and binds permanently within two years. Storage of H2S worked even better.”

In other words, greenhouse gases turn to stone, opening up vast opportunities. Basalt covers most of the world’s seabed and roughly 10 per cent of the continents, says Ms Snæbjörnsdottir.

As one participant at the NORDICCS conference put it, “This is a finding that should have an impact at the UN Paris Climate Change Conference in December.”